Impact of clinical utility of MRD assessment with different techniques on survival in acute B lymphoblastic leukemia.

We investigated the impact of minimal residual disease (MRD) obtained from different approaches on the outcomes of 141 B lymphoblastic leukemia (B-ALL) patients. Among 169 samples with more than 5% blasts by morphology, 3.6% (6/169) were Flow-MRD negative. Of the 212 positive molecular-MRD samples from Ph+ ALL patients, 55 (25.9%) were Flow-MRD negative. Before consolidation or allogeneic stem cell transplantation (allo-HSCT), negative Flow-MRD was associated with improved survival (p = .019 and .041, respectively) for Ph- ALL patients, but not for Ph+ ALL (p = .111 and .812, respectively). There was no difference in overall survival (OS) by achievement of complete molecular response at complete remission (CR, p = .333 and .863, respectively). Our results indicated that the results of MRDs detected with different methods varied. Flow-MRD can be used as a reliable prognostic marker for Ph- ALL patients. MRD either by flow cytometry or quantitative reverse transcription-polymerase chain reaction (qRT-PCR) at CR did not affect OS or DFS for Ph+ ALL.